1. Field of the Invention
The present invention relates to locks which can be attached to vehicles such as motorcycles. More specifically, it relates to locks that incorporate an alarm system.
2. Related Art
In the prior art, locking devices have been attached to wheels of motorcycles and the like to prevent theft, including locks that were equipped with an alarm which would sound when the lock was moved. FIG. 6 is a simplified diagram of a conventional lock equipped with such an alarm. As is shown in the figure, when closed, the lock forms a U-shaped ring, and when it is installed around a vehicle wheel (not shown), the lock immobilizes the vehicle. After the vehicle has been parked, the approximately U-shaped shackle or bar 31 is attached through the inside of the wheel and then the left and right ends of the bar are inserted into a locking member body 32 located outside of the wheel. This locking member 32 is equipped with a sensor, alarm, and electronic parts to control them located inside a housing member 33. When the alarm is set, if the sensor detects any vibration, tilt or other motion of the lock, an alarm is sounded to deter theft.
However, such locks of the prior art attach or include the alarm to or with the lock itself, and breaking the lock may destroy the alarm, or, the alarm can be covered with cloth to mute its volume and thereby reduce its ability to deter theft.
Further, since the alarm must emit sound as a warning, it is not possible to provide a completely sealed, waterproof structure. Accordingly, moisture can enter the locking device and may deteriorate the lock or produce operational failure.
In addition, because the alarm requires relatively high electric power to operate and since there is limited space available inside the lock for housing the power source such as batteries or the like for the alarm and sensor, there are limitations on the length of time the alarm can operate and upon the sound level it can generate.
Furthermore, since a housing member has to be attached to the lock to house the alarm, the size of the lock is thereby increased considerably.
The present invention was developed to address the above described issues in the prior art, and it has as its objective the provision of an alarm system for locks which will sound the alarm even if the lock is broken, which imposes no restrictions upon the alarm's time of operation or sound level, and which does not increase the size of the lock.